> Actually I really wanted to know how compatible different versions of Linux
> are.
Keep this in mind: Linux is the kernel, RedHat, Debian, Mandrake are
distributions (or flavors), and all can use the same kernel.
> As in, if I have old hardware and get the source for a driver, will I
> be able to keep it working into the future.
Yes. Exactly. If you get a binary only, that is when you get stuck.
> Or are the drivers for Red
> Hat, Debian, and Mandrake so different that one would really have to
> rewrite the driver from scratch for each one of them. I would guess that
> Linux 2.2... would take the same drivers no matter who did the
> distribution.
exactly. At the driver level, they are all the same. At the application
level, they are mostly the same, with some minor (and sometimes
annoyingly) differences. The Linux Standard Base (LSB) project is meant
to make a uniform 'Linux' so that you don't end up with software that
'only runs on Red Hat' for instance.
Keep in mind, the real problem is usually upgrading kernels. 2.0 is
radically different from 2.2 is radically different from 2.4. However,
backward compatiblity is usually there, so it's not a big deal.
Xfree 4.0 doesn't support some cards that 3.3.6 does, so this isn't
unique. Every new version of anything usually will break _something_.
Except Windows.
They didn't breaking anything by upgrading. It was already broken. :)
